| 摘要 |
PURPOSE:To reduce noise generated by isolation of the flow of the air generated in the surface of an orifice disposed at the periphery of the impeller of an air supplying apparatus. CONSTITUTION:An orifice 9 is formed of two arc-shaped parts 9a, 9b having different curvatures of sectional shapes at the axial direction of an impeller 3 in such a manner that the curvature R2 of the part 9b of the downstream side to the impeller 3 is larger than the curvature R1 of the part 9a of the upstream side, thereby eliminating the disorder such as the isolation of the flow of the air on the surface of the orifice 9. |
